Cassette transfer mechanism

Abstract

The cassette transfer mechanism of the present invention comprises a cassette chamber for housing a cassette storing a plurality of substrates, a liftable stand capable of moving up and down in the cassette chamber, a cassette holder having a bottom-surface supporting portion for supporting a bottom-surface of the cassette and a back-surface supporting portion for supporting a back-surface of the cassette, and a moving mechanism provided outside the cassette chamber and rotatably supporting the cassette holder, for moving the cassette holder between a waiting position outside the cassette chamber and the liftable stand inside the cassette chamber, wherein the moving mechanism has rotation mechanism for rotating the cassette holder around an axis crossed virtually in perpendicular to an axis extending along the moving direction of the liftable stand.

We claim: 
     
       1. A cassette transfer mechanism comprising: a cassette chamber having a housing which forms a storing space for housing a cassette storing a plurality of substrates, a cassette loading entrance which is formed in the housing and allows the cassette to be loaded into and unloaded from the storing space, and a substrate unloading opening which is formed in the housing and allows at least one of the substrates to be loaded into and unloaded from the storing space;   a liftable stand arranged in said storing space of the cassette chamber and being capable of moving up and down between a cassette receiving position for receiving the cassette and a position for unloading said at least one of the substrates through said substrate unloading opening;   a cassette holder having a bottom-surface supporting portion for supporting a bottom surface of the cassette and a back-surface supporting portion for supporting a back surface of the cassette; and   a moving mechanism provided outside the cassette chamber, said moving mechanism rotatably supporting the cassette holder and transferring the cassette on the cassette holder to the liftable stand at the cassette receiving position by rotating from a waiting position outside the cassette chamber to the cassette receiving position inside the cassette chamber through the cassette loading entrance,   wherein said moving mechanism has rotation means for rotating the cassette holder around an axis approximately perpendicular to an axis which extends along the moving direction of the liftable stand.   
     
     
       2. The cassette transfer mechanism according to claim 1, wherein said liftable stand is rotatable around the axis extending along a moving direction of the liftable stand. 
     
     
       3. The cassette transfer mechanism according to claim 1, wherein a hole which permits the liftable stand to move up and down, is formed through the bottom-surface supporting portion of the cassette holder. 
     
     
       4. The cassette transfer mechanism according to claim 3, wherein said hole of the bottom-surface supporting portion is a U-shaped type having a pair of open ends. 
     
     
       5. The cassette transfer mechanism according to claim 1, wherein said rotation means rotates the cassette holder by 90 degrees. 
     
     
       6. The cassette transfer mechanism according to claim 5, wherein said rotation means rotates the cassette holder by 90 degrees when the cassette holder is moved from the waiting position to the liftable stand by the moving mechanism, with the result that the cassette, which is horizontally supported by the back-surface supporting portion of the cassette holder in the waiting position, is changed to being horizontally supported by the bottom-surface supporting portion of the cassette holder. 
     
     
       7. The cassette transfer mechanism according to claim 1, wherein said moving mechanism consists of a main driving axis rotatably supported at a portion outside the cassette chamber,   a main driving portion for rotating the main driving axis,   a pair of first arm members each having one end fixed on the main driving axis and the other end rotatably connected to the cassette holder,   a pair of second arm members each having first and second ends, the first end rotatably connected to the main driving axis,   a fixed axis having two ends to which the second end of each of the second arm members is connected,   a third arm member having one end rotatably connected to the fixed axis and the other end rotatably connected to the cassette holder, and   a rotation driving portion for rotating the second arm members.   
     
     
       8. The cassette transfer member according to claim 7, wherein said rotation driving portion consists of a sub driving axis rotatably supported by a portion outside the cassette chamber,   a sub driving portion for rotating the sub driving axis,   a gear fixed on the sub driving axis, and   teeth engaged with said gear and formed at one end of the second arm members.   
     
     
       9. The cassette transfer mechanism according claim 7, wherein said rotation means rotates the second arm member around said main driving axis to operate the third arm member, thereby rotating the cassette holder around a connecting portion thereof with the first arm member. 
     
     
       10. A cassette transfer mechanism comprising: a cassette chamber having a housing which forms a storing space for housing a cassette storing a plurality of substrates, a cassette loading entrance which is formed in the housing and allows the cassette to be loaded into and unloaded from the storing space;   a liftable stand arranged in said storing space of the cassette chamber and being capable of moving up and down between a cassette receiving position for receiving the cassette and a position for unloading said at least one of the substrates;   a cassette holder having a bottom-surface supporting portion for supporting a bottom surface of the cassette and a back-surface supporting portion for supporting a back surface of the cassette; and   a moving mechanism provided outside the cassette chamber, said moving mechanism rotatably supporting the cassette holder, for moving the cassette holder between a waiting position outside the cassette chamber and the liftable stand inside the cassette chamber and transferring the cassette on the cassette holder to the liftable stand at the cassette receiving position by rotating from a waiting position outside the cassette chamber to the cassette receiving position inside the cassette chamber through the cassette loading entrance,   wherein said moving mechanism has rotation means for rotating the cassette holder around an axis approximately perpendicular to an axis which extends along the moving direction of the liftable stand.